In the description that follows reference is made to certain structures and methods, however, such references should not necessarily be construed as an admission that these structures and methods qualify as prior art under the applicable statutory provisions. Applicants reserve the right to demonstrate that any of the referenced subject matter does not constitute prior art.
Smoking articles, such as cigarettes or cigars, produce both mainstream smoke during a puff and sidestream smoke during static burning. One constituent of both mainstream smoke and sidestream smoke is carbon monoxide (CO). The reduction of carbon monoxide in smoke is desirable.
Catalysts, sorbents, and/or oxidants for smoking articles are disclosed in the following: U.S. Pat. No. 6,371,127 issued to Snider et al., U.S. Pat. No. 6,286,516 issued to Bowen et al., U.S. Pat. No. 6,138,684 issued to Yamazaki et al., U.S. Pat. No. 5,671,758 issued to Rongved, U.S. Pat. No. 5,386,838 issued to Quincy, III et al., U.S. Pat. No. 5,211,684 issued to Shannon et al., U.S. Pat. No. 4,744,374 issued to Deffeves et al., U.S. Pat. No. 4,453,553 issued to Cohn, U.S. Pat. No. 4,450,847 issued to Owens, U.S. Pat. No. 4,182,348 issued to Seehofer et al., U.S. Pat. No. 4,108,151 issued to Martin et al., U.S. Pat. No. 3,807,416, and U.S. Pat. No. 3,720,214. Published applications WO 02/24005, WO 87/06104, WO 00/40104 and U.S. Patent Application Publication Nos. 2002/0002979 A1, 2003/0037792 A1 and 2002/0062834 A1 also refer to catalysts, sorbents, and/or oxidants.
Iron and/or iron oxide has been described for use in tobacco products (see e.g., U.S. Pat. Nos. 4,197,861; 4,489,739 and 5,728,462). Iron oxide has been described as a coloring agent (e.g. U.S. Pat. Nos. 4,119,104; 4,195,645; 5,284,166) and as a burn regulator (e.g. U.S. Pat. Nos. 3,931,824; 4,109,663 and 4,195,645) and has been used to improve taste, color and/or appearance (e.g. U.S. Pat. Nos. 6,095,152; 5,598,868; 5,129,408; 5,105,836 and 5,101,839).
Despite the developments to date, there remains a need for improved and more efficient methods and compositions for reducing the amount of carbon monoxide in the mainstream smoke of a smoking article during smoking.